docs: def inner_horizontal_border(self):
          """
          The complete inner horizontal border section, including the left and right border verticals.
  
          Returns:
              str: The complete inner horizontal border.
          """
          return u"{lm}{lv}{hz}{rv}".format(lm=' ' * self.margins.left,
                                            lv=self.border_style.outer_vertical_inner_right,
                                            rv=self.border_style.outer_vertical_inner_left,
                                            hz=self.inner_horizontals())